The present invention broad relates to trailers adapted to be towed by a vehicle. In particular the present invention relates to articulated boat trailers. Prior art relevant to the herein disclosed invention can be found in U.S. patent class 280 subclasses 103, 414 and 445.
The art is replete with trailers to perform various tasks, including transporting sailboats. Generally such trailers employ bunks to cradle the sailboat and a single or tandem axle arrangement disposed between the rear and the mid point of the trailer. Additionally, the art discloses various arrangements to steer the wheels of an articulated axle disposed toward the front of a trailer. The wheels of some of these steerable axles are lockable in a "straight ahead" position. Of course it is well known in the prior art to dispose a jack at the front of a trailer. Additionally, various means to accomplish the disposition of this jack and numerous jack related structures are present in the prior art. Another addition made to many boat trailers is an extensible tongue. When the tongue is extended the boat is relatively far down a boat ramp in respect to the tow vehicle.
Miller U.S. Pat. No. 4,094,527 discloses a sailboat trailer. In particular, this trailer has a rocker system for centering the keel of the sailboat. This patent is illustrative of the numerous trailer patents issued over the years.
Various systems for providing steering to a steerable trailer axle are disclosed in Baker, U.S. Pat. No. 4,208,063; Drewek, 4,042,255; Folkert, 3,753,580 and Schramm, 3,105,704. Some draft type steerable axles are disclosed in Jacobs, U.S. Pat. No. 1,856,997; Kelsy, 2,608,417; and Ronning, 2,650,100.
Most illustrative of these steering mechanisms and draft mechanisms is Barker U.S. Pat. No. 2,734,754. This is a pivotally connected draft tongue with selective steering mechanism. It discloses a locking mechanism for the front wheels of a trailer during backing operations.
Faurenhoff U.S. Pat. No. 4,961,589 discloses am attachment for the base of a trailer jack. This attachment allows the tongue of the trailer to be adjusted in a horizontal plane to facilitate hitching or trailer placement.
Spear U.S. Pat. No. 3,826,470 discloses a scissor type trailer jack which stows in a horizontal position.
Merrill U.S. Pat. No. 5,087,063 speaks to a retractable jack and support for trailer tongues.
Halloway U.S. Pat. No. 5,013,011 discloses a self-deploying stabilizing jack. This jack is intended for use by Recreational Vehicles or other similar vehicles.
Nudd U.S. Pat. No. 5,067,692, discloses a jack employing a bracket to facilitates disposing the jack in a vertical or horizontal position. The horizontal position in this instance is used only for storage.
The prior art boat trailers have several shortcomings. For example, the load of a conventional trailer needs to be more or less centered over the axles of the trailer to provide the proper tongue weight. If the tongue weight is too great or too little the trailer is difficult to control. Conventional trailers often drag due to excessive overhang behind the axle. Articulated or steerable axle trailers are difficult to back. Furthermore, extending the trailer tongue length on many conventional trailers is not practical due to the strength required for such an unsupported span. Additionally, ground clearance for the extension as the trailer starts down an incline such as a boat ramp is troublesome.
Therefore, a trailer with a front axle which pivots to steer front wheels is desirous to improve cornering, weight distribution characteristics and clearance. It is further desirous to provide the trailer with a jack to raise the trailer on one or more pivoting wheels. This will provide ground clearance under the front tires so the axle can be locked in a straight position. As a result during backing operations the trailer will handle similar to a conventional single or double axle trailer. The desired configuration would also prevent "high centering" of the trailer frame as it passes over an incline such as a boat ramp.